1. Field of the Invention
This invention relates generally to the utilization of an adaptive receiving antenna in a receiving station to receive a useful telecommunications signal transmitted by a transmitting station and combined during transmission with a disturbing signal.
2. Description of the Prior Art
It is known in the prior art in the radar field to use an adaptive receiving antenna including a plurality of primary sources feeding a plurality of corresponding reception paths. Due to the distances between the various primary sources on the antenna, the telecommunications signals picked up by the primary sources are relatively out-of-phase and must be matched in phase by comparison with a reference phase in order to sum the received signals into a received signal having a maximum power. Since transmitting and receiving "stations" of a radar are close together, the reference phase is that of the useful transmitted signal which has the same waveform, to within amplitude, as the received signal.
However, in telecommunications systems involving distant transmitting and receiving stations, the receiving station does not know the exact frequency of the transmitted useful signal. Indeed, in the telecommunications field, the nature of the received signal is never completely known a priori, since the purpose of a transmission is precisely to send information from a transmitting station to a receiving station in the form of a sequential modification of the transmitted telecommunications signal i.e., the useful signal.
Moreover, the useful signal received at the receiving station can be degraded by at least one disturbing signal located outside the frequency band of the transmitted signal, in accordance with the standard radiofrequency scheme. Hereafter, in the present specification and claims, such a signal that is located in a frequency band outside of the frequency band of the transmitted useful signal and which arrives at a receiving antenna from a direction different from the direction of the useful signal, to degrade the useful transmitter signal received at the receiving station, is referred to as a disturbing signal. To process the useful signal emitted by the transmitting station and received together with the disturbing signal at the receiving station, it is necessary to attenuate or even eliminate the disturbing signal in the receiving station.